Also get coverage on oldest deps

Author: mkelley

.github/workflows/ci_tests.yml

@@ -54,8 +54,8 @@ jobs:
           linux: py311-test-numpy126-alldeps-cov
           coverage: codecov
 
-        - name: Python 3.9 with oldest supported versions
-          linux: py39-test-oldestdeps
+        - name: Python 3.9 with oldest supported versions, measuring coverage
+          linux: py39-test-oldestdeps-cov
   macos-test:
     name: Python 3.11 with all optional dependencies (MacOS)
     needs: [oorb-data]